Carl Levin Sen. Carl Levin is certainly concerned about climate change, but it’s unclear whether he will support the Kerry-Boxer climate bill. In this letter sent to a constituent in early November 2009, the senator stresses that other nations must commit to binding greenhouse-gas limits. He calls for a climate bill that will account for regional differences in the U.S., impose tariffs on goods from countries that haven’t committed to action, and preclude states from setting their own, tougher standards for automobile emissions (California, he’s talking to you): Dear [Constituent], Thank you for contacting me regarding global climate change. There …